The present invention relates to a a disposable type syringe where two components, for example, a solid medicine and a liquid solvent are previously filled respectively into separate dual-chambers.
Conventionally powdered medicine, liquid solvents and injection cylinder are normally used when powdered injection medicines are given. The powdered medicines are filled aseptically into a vial or an ampule container. As liquid solvents, distilled water for injection or an isotonic sodium chioride solution are filled aseptically in an ampule or the like. A so-called disposable syringe of a disposable type is overwhelmingly used nowadays from a point view of safety as an injection cylinder.
The injection against to human body or the like is effected with the following procedure. They are taken out of sealed bags or outer boxes. A disposable injection needle is mounted on a disposable syringe, and the neck portion of an ampule with a liquid solvent being contained in it is cut. The solvent is aspirated with a disposable syringe with a needle attached to it. Then, the injection needle of the disposable syringe is penetrated through the rubber stopper of a vial with powdered medicine being contained in it so as to inject the liquid solvent into the interior thereof. The powdered medicine is sufficiently dipped, dissolved into the liquid solvent in the vial. Thereafter, the solution is aspirated, picked into an injection cylinder to draw out the air so that the injection is effected.
This is a conventional injection operation normally effected. This operation takes more time, with a problem even in terms of cost, and contamination of glass pieces at ampule break time.
As a method of solving such problems, a dual-chamber type of prefilled syringe is found out. But in the present time point, the demand in this type of syringe is not satisfied completely.
These requirements are as follows.
1. Both powdered medicine and liquid solvent must be heremetically sealed and kept in a sterile condition until ready for injection.
2. It must provide for safe sealing of the material to prevent accidental mixture before time for use.
3. The integrity of the system should be preserved to prevent contamination of the material from outside sources, including the atmosphere during storing, mixing and injection.
4. The injection needle must be kept sterile until injection is effected.
5. The syringe must be compact and completely packaged in a single unit before use.
6. It must provide for adequate mixing and dissolving of the materials.
7. It must be simple and operable by medical personel in a conventional manner.
8. It must be simple and economical to manufacture.
9. It must be rigid and capable of withstanding shipment and handling by personnel.
10. The combination of medicament, diluent, rubber and glass should not combine to cause a particulate matter problem.
11. Once activated the unit should provide drug stability and pharmacological potency at room temperatures for at least eight hours.
12. It should not be subject to accidental activation, contamination, malfunction or disassembly.
13. It should have product stability capable of going to two years.
14. It must not require abnormal storage condition or handling.
15. It must have all components pre-attached so that no assembly is required for use.
16. The need to remove any parts prior to use should be minimal.
17. It should be capable of adapting to existing manufacturing process, knowledge and skills, including filling equipment.
18. It should be functional with presently approved rubber compound formulations.
Proposals for satisfying some of the above described demand items are already made. The representative ones are as follows.